Electrostatic apparatus



n Ill!!! I'll!!! A I 7 F. BANNEITZ ELECTROSTATIC APPARATUS Filed Sept 1 1921 Nov. 9, 1926.

Patented Nov. 9, 1926.

UNITED STATES 1,605,911 PATENT OFFICE.

FRITZ BANNEITZ, OF BERLIN-SCHONEBERG, GERMANY.

ELECTROSTATIC APPARATUS.

Application filed September 1, 1921, Serial No. 497,797, and in Germany December 24, 1919.

The invention relates to improvemcntsin electrostatic apparatus. The application of electrostatic apparatus (measuring instruments. relays and the like) is frequently prevented by the fact that their scnsitiveness is not sufiicient. The sensitiveness of such apparatus has hitherto been increased by reducing the distance between the electrodes. by enlarging the electrodes 01' by separating the electrodes by a medium of a high dialectric constant. This invention points out a new road to increase the sensitiveness of an electrostatic apparatus.

It is well known that the electrostatic attraction of two parallel plates takes place according to the law 76: fe. 81ra V in which formula fzarea of the plates, (1,: the distance between them, Y the potential difference and ezdielectric constant of the medium between the plates. In certain circumstances which will be described further on an apparent deviation from this law takes place, inasmuch 'as the mutual attraction of the electrodes is increased by a partial conductivity of the medium situated between them.

The utilization of-this increased force generated by a partialconductivity of the medium in electrostatic apparatus, more particularly in relays, forms the object of this invention. The invention consists essentially in disposing between the electrodes contained in a closed chamber, of which at least one is movable, a liquid or gaseous medium,

which consists of layers one or more of which are poor conductors of electricity, while the other layers are good conductors. These layers distinguished by different conductivity may either be produced by differentsubstances, which are disposed between the electrodes or they are produced in the originally homogeneous medium by voltages connected with the electrodes.

If two opposite plates (electrodes) are disposed in a chamber containing rarefied gas, a stronger attraction of the electrodes takes place at certain pressures than couldbe anticipated according to the above law. The pressure required is more or dependent upon the connected voltage, the distance be-- tween the electrodes and in certain circumstances upon the area of the electrodes, upon the gas and upon the degree of ionization of the gas. The generation of this effect is brought about or facilitated, especially in the case of low voltages by an artificial ionization of the space between the electrodes by means of ionized rays or preparations. At a very high vacuum a comparatively high voltage is necessary for obtaining the effect required. but here also the effect may be obtained by an incandescent electrode.-

If a conductive gas of atmospheric pressure is disposed between the electrodes, the effect is likewise observed and more so when the connected potentials or the auxiliary potentials are brought to the most favorable value for the distance between the electrodes.

The ionization of the electrode space may be effected in various manners: either directly between the plates by Rontgen rays or a radio-active preparation or a gas made conductive at another. place conducted between the electrodes.

The same effect may also be obtained by a conductive liquid between the electrodes,

provided that by its electrolytic decomposition no other undesirable results appear.

The generation of this increased power effect apparently depends upon the presence of a non-uniform potential vessel between the electrodes which is probably characterized by the feature that next to a good conducting layer there is a very thin poorly conducting layer which is produced by the field of the connected voltage. This explanation gains in probability by the fact that the effect may comparatively easily be obtained, if a thin insulating layer is inserted between the electrodes disposed in a conducting, medium. From this follows one constructionof apparatus in such a manner, that one or more thin layers of an insulating or badly conducting material is put between or upon the electrodes. The main parts of the apparatus are the two electrodes which face each other at a short distance apart. One of these electrodes is fixed, the other movable in such a manner that owing to the attraction it can approach the fixed one within narrow limits. The movable electrode operates for instance a pointer, if the apparatus is employed as a measuring instrument,and opens and closes a contact with which the circuit to be controlled is connected, if the apparatus is to be employed as a relay.

In the accompanying drawing the imthe free end of a flat spring 3, which acts in opposition to the attraction of the fixed electrode and thus maintains the movable electrode in its position of rest. In order that the connected voltage may only act between the two electrodes the latter are surrounded by a protective casing 4 which prevents discharges alon other paths. The fiat spring 3 1s provi ed with a contact 5, which when the electrode 2 is not attracted, abuts against the contact point 6. If 9. voltage is connected with the electrodes 1 and 2 across the conductors 7 and 8, the electrode 2 is attracted and the contact 5.6 interrupted in the rythm of the oscillations-of the connected voltages and thus a second circuit cont-rolled across the conductors 89. The

whole apparatus is disposed insidea vessel, in which the suitable medium according to I the invention is contained. 1

Referring to Fig. II, itwill be seen thatthe electrodes 1 and 2 are disposed horizontally, while the attraction of the.fixed electrode 1 upon the movable electrode 2 is conpensated for by a helical spring 11. The relay contact 5 is fixed upon the guide-sleeve 12 and operates with the vertically disposed' contact 6.

In Fig. III the balancing device for the 4 movable electrode is similar to the one shown in Fig. II and the rela contact 5 is fixed upon the electrode 2, while the relay contact 6 is disposed the same as in Fig. II. v The fixed electrode is constructed as a grid and below it is disposed an incandescent wire 13 adapted to be heated from the outside, by means of which and a high vacuum the electrode space is made conductive.

In Fig. IV the movable electrode 2 is disposed between two fixed electrodesl and 1 correspondmg to a polarized. relay. Op-

? posite potentials are connected with the fixed otentials to be conwith the movable electrodes, while the trolled are connecte electrode. i

It is to be understo'od thatthe details of the apparatus may be modified without departing from the spirit of-the'invention.

. What I claim as my-invention and desire .to secure by- Letters Batent is:

. 1. An electrostatic device comprisingan. I

enclosed chamber containing an ionized gaseous medium, a pair of electrodes mounted within said chamber, said electrodes each having an extended surface, the extended surfaces of said electrodes being disposed in opposite relation, at least one of said electrodes being vmovable toward and away from the other of said electrodes, and means for efi'ecting circuit connections with said electrodes, said electrodes being movably attracted toward each other in response to the application of a difi'erence of potential therebetween.

2. An electrostatic device comprising an enclosed chamber containing a conductive gaseous medium, a pair of electrodes mounted within said chamber, said electrodes each having an extended surface, the extended surfaces of said electrodes being disposed in opposite relation, oneof said electrodes being fixed, the otherof said electrodes being movable toward and away from said fixed electrode, and means for. eifecting circuit connections with said electrodes, said movableelectrode being operable to move toward said fixed electrode inresponse to the application of a difference of potential between said electrodes.

3. An electrostatic device comprising an enclosed chamber containin a gaseous medium, which when ionized ecomes conduc tive, an' incandescent filament in said chamber for ionizing the, gaseous medium, a pair of electrodes mounted within said chamber, said electrodes each having an extended surface, the extended surfaces of said electrodes being disposed in opposite relation, one of said electrodes being fixed, the other of said electrodes being movable toward and away from said fixed electrode, means for efiecting circuit connections with said electrodes, said movable electrode being operable to move toward said fixed electrode in proportion to the difference of potential between said electrodes, and a contact operable in response to movements of said movable electrode.

4. An electrostatic device comprising an enclosed chamber containing a conductive gaseous medium, a pair of electrodes mounted within said chamber, each of said electrodes'having an extended surface, the extended surfaces of said electrodes being disposed in substantially parallel relation and out of contact one with theother, one of said electrodes being fixed, the other of said electrodes being yieldably mounted and movable toward said fixed electrode in response to electrostatic attraction therebet-ween, means for effectin circuit connections with said electrodes, an a contact operable in response to movements of said movable electrode.

In testimony whereof I afiix my signature.

Di. .FnI-rz BANNEITZ. 

